I know HN has special rules for formatting certain URLs. Like Twitter links get the username added on and apparently research.google.com gets a subdomain (Or maybe all of Google?).

Turns out this link is actually from colab, a repository of user-generated content hosted at colab.research.google.com.

@dang: if it isn't too unwieldy, maybe colab links could have the 'colab' part added on too? The way it is now led me to think the link led to an official Google Research publication/project.